naa a22 4500 510790534 CHVBK 20180411083318.0 cr unu---uuuuu 180411e20131101xx s 000 0 eng 10.1134/S1063773713110078 doi (NATIONALLICENCE)springer-10.1134/S1063773713110078 FG SGE: Evolution of the circumstellar dust shell ( JHKLM Photometry in 1985-2013) [Elektronische Daten] [O. Taranova, V. Shenavrin] Long-term (1985-2013) JHKLM photometry for FG Sge is analyzed. Parameters of the supergiant and optical properties of the dust in the dust shell (DS) have been refined. Given the optical photometry, the spectral energy distribution of FG Sge at J brightness maxima in the range 1.25-5 µm is consistent with the classification of the supergiant as a K3 star. It is shown that the observed changes in J and H magnitudes in 1993-2013 can be explained by the joint action of two factors: the absorption of emission from the supergiant in the DS with dust grains similar to interstellar ones and the changes in parameters (spectral type and radius) of the supergiant itself. The DS has a clumpy structure, its temperature changed within the range 450-800 K, and its radius changed by a factor of 3. The optical depth of the DS estimated from its emission changed within the range τ em(J) ≈ 0.8-3; its changes on the line of sight were τ ext(J) ≈ 0-5. On average, the rate of dust supply to the DS from 1998 to 2013 was 10−6 M ⊙ yr−1. Pleiades Publishing, Inc., 2013 post-AGB stars nationallicence infrared emission nationallicence variability nationallicence dust shells nationallicence Taranova O. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut Shenavrin V. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut Astronomy Letters Springer US; http://www.springer-ny.com 39/11(2013-11-01), 781-791 1063-7737 39:11<781 2013 39 11443 https://doi.org/10.1134/S1063773713110078 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1134/S1063773713110078 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Taranova O. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut NATIONALLICENCE 700 1- Shenavrin V. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut NATIONALLICENCE 773 0- Astronomy Letters Springer US; http://www.springer-ny.com 39/11(2013-11-01), 781-791 1063-7737 39:11<781 2013 39 11443 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer